Tuesday, December 25, 2007

Call for research after mass bird deaths

By Brian Unwin

Thousands of British seabirds have washed up dead on shorelines sparking calls for more international research into problems that could lead to future population crashes.

Dead birds that were found on the Scandinavian coast

The discovery of thousands of dead and dying auks, mainly razorbills, around the coasts of Denmark, southern Norway and Sweden, in September and October, didn't arouse widespread UK attention because there was comparatively little evidence of problems on this side of the North Sea.

But alarm bells rang after the latest British Trust for Ornithology BirdTrack Update referred to "a large wreck of auks seen along the north and east coasts, and as far afield as the Oslo fjord … All of these appear to have starved - and most were adults."

This disaster was of UK significance because, after the breeding season's end, Scotland's razorbills head for Scandinavian waters. This was underlined by numbered rings on several corpses: one started life on the Shiant isles off Lewis in the Outer Hebrides in 1982; another on the Isle of May off Fife on the mainland's east coast in 2000.

What caused particular concern, however, was that the birds were in an emaciated state - indicating failure to catch sufficient small fish to fuel their life on the open sea - and almost all were adults.

Normally such disasters are associated with protracted severe weather in deep mid-winter; to have happened in the autumn suggested most exceptional circumstances.

Kjell Isaksen, the Oslo municipality's biologist and wildlife manager, said "massive" number of dead and dying razorbills were washed ashore in his area. "Razorbills and guillemots were also seen on lakes far inland or found grounded on fields."

He had examined externally 60 per cent of 500 dead razorbills picked up locally and noted they were "only skin and bone", so emaciated he was surprised that birds originating in Scotland had been able to reach Norway. The conclusion in every case was "death by starvation."

"It seems clear that the massive movement must have been initiated by large scale food shortage in the area were these birds stayed - probably the North Sea or West Skagerrak.

"The fact that they turned up along our coasts was probably more or less a coincidence due to the prevailing wind direction."

Dr Tycho Anker-Nilssen, a Norwegian Institute for Nature Research senior research scientist, who will examine 400 of the corpses, said establishing their origin would be a top priority.

An unknown number - possibly thousands - may have died at sea and vanished without trace.

RSPB Orkney officer Eric Meek commented: "There is absolutely nothing here to indicate that this is anything other than a food shortage-related incident. All the birds we have handled have been very thin and they are dying in the classic way in starvation incidents."

A few weeks after razorbills washed ashore at Orkney, dead puffins started appearing also. "This was interesting because puffins usually disperse out to sea and head in a generally southerly direction."

As with the razorbills in Norway, measurements of 50 puffin corpses found at Scapa Flow produced surprises. "Many of the adults were in complete moult - and therefore flightless - which was about three months out of sync with what is known of puffin moult. It seems to suggest these birds were under some particular form of stress."

Martin Heubeck, an Aberdeen University seabird specialist was alerted to the razorbill "wreck" in southern Scandinavia by a contact in Sweden who told of "extraordinary numbers" arriving there.

He stressed this disaster showed the need for the organisation of co-ordinated surveys of coastlines on both British and European sides of the North Sea each autumn to monitor what happens to auks dispersing from their breeding colonies - "something I've been recommending for 20 years."

However, the RSPB, which organises a national beached birds survey every February, is reluctant to expand this. Spokesman Grahame Madge said: "Finding enough volunteers to turn out in February is hard enough - organising such an operation at other times of year as well would be even more difficult.

"A better policy would be increased research into why certain seabird species are failing to find food."

Norway's Dr Anker-Nilssen commented: "A lot of work remains before we understand in more detail the mechanisms behind these worrying problems for seabirds in the North Sea and west Nordic waters in general."

"So the challenge for marine scientists in general, including seabird ecologists, is huge. I am, however, much more optimistic these days than only a few years ago that we will get there eventually - hopefully in time to avoid that we contribute to 'irreversible' processes that reduce the great value and importance of these environments."


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